drivers/sensor: lps22hh: Fix the raw to kPa sample conversion
drivers/sensor: lps22hh: Fix the raw to kPa sample conversion

The lps22hh 24 bit raw sample is left aligned, which means that
it needs to be right-shifted by 8 before applying conversion.
Moreover the conversion has been simplified for clarity.

Fix #35871

Signed-off-by: Armando Visconti <d93ca24ded08d03c3aa60af6d2fd0eb7ce54da11@st.com>

zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr